介绍了将LPG应用在小型点燃式发动机上时 ,对燃烧系统参数优化和稀薄燃烧能力的影响。试验在一台四冲程、水冷 1 2 5ml单缸摩托车发动机上进行。研究结果表明 ,压缩比和点火提前角的增大有利于恢复发动机扭矩 ,火花塞间隙调整对扭矩影响不明显 ;提高压缩比、增加点火提前角和加宽火花塞间隙将有利于LPG在发动机中拓宽稀薄燃烧区的范围 The effect of LPG on the combustion system parameters optimization and lean burn capacity is introduced when it is applied to a small spark ignition engine. The test was carried out on a four-stroke, water-cooled 125 mm single cylinder motorcycle engine. The results show that the increase of compression ratio and ignition advance angle is helpful to restore the engine torque, and the spark plug gap adjustment has no obvious effect on the torque. Increasing the compression ratio, increasing the ignition advance angle and widening the spark plug gap will help LPG to widen the thinning in the engine Burning zone range